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Finding the Fourth Proportional to 2,160, 2,980.86 and 1,215.78

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Solution

The fourth proportional to 2,160, 2,980.86 and 1,215.78 is: 1,677.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    2,160 : 2,980.86 = 1,215.78 : x
  2. Step 2: Convert to fraction form
    2,160/2,980.86 = 1,215.78/x
  3. Step 3: Cross multiply
    2,160x = 2,980.86 × 1,215.78
  4. Step 4: Simplify right side
    2,160x = 3,624,069.97
  5. Step 5: Solve for x
    x = 3,624,069.97/2,160
  6. Step 6: Final answer
    x = 1,677.81

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.